VALUE OF NORWEGIAN LAKES FOR FISH CULTURE. 581 



sired quantity of impregnated eggs. If we estimate that only 2,000,006 

 eggs are sold annually at the lowest price, these yield a gross profit of 

 $16,000, or $800 per hectare ($80 per rood) of the whole property, which 

 can only be in part occupied by them for the necessary fish-culture ponds. 



Mr. Green states that a pear-shape basin of C.3 meters in length, 1.9 

 meters in breadth about the middle, and from 0.15 to 0.64 of a meter in 

 depth, with a capacity about 3.6 cubic meters, and with a water sujjply 

 of 1.6 liters of filtered spring water per second is quite sufficient for 6,000 

 to 8,000 young after they are completely hatched, when they begin to 

 take food of their own accord. 



That a similar pear-shape basin of 9i meters in length, 3.15 meters in 

 breadth at about the middle, and a depth 0.15 to 1.26 meters, with a ca- 

 pacity about 15i cubic meters, and a water supply of about 37^ liters of 

 brook water in a second, will be sufficient for 5,000 two-year old fish ; 

 while a similar basin 15.75 meters long, 9.5 broad about the middle, and 

 from 0.15 to 1.5 meters deep, with a capacity about 48 cubic meters, and 

 a supply of running brook- water equal to that of the last smaller basin, 

 is fully sufficient for 2,000 fish in the third year; observe, under the con- 

 dition that the temperature of the water is not under 1° (34.25° F.) and 

 not over 12° R. (59° F). The fish will die if the temperature of the water 

 rises to 16° R. (68° F.), unless there are cold springs in the bottom of the 

 basin which will cool off the water. The rule is, the colder the better 

 down to the limit stated. 



The hatching is tlone in a trough 20 feet long, 18 inches broad, and 6 

 inches deep, which is divided into compartments 18 inches long by cross- 

 pieces 2 inches high, which are secured to the sides of the trough ; other 

 such cross -ineces are used at pleasure, or when it is necessary to make 

 the water deeper. The bottom of the trough is covered with shingle. 

 The spring water is filtered in a trough 6 feet long, in which are placed, 

 at an angle of 45°, three to four screens covered with flannel, to give the 

 greatest possible filtering surface. The loss of eggs in hatching does not 

 exceed 6 j^er cent. 



Later, Mr. Green was appointed superintendent of the fisheries of New 

 York State, and he constructed a State hatching-house on the same 

 brook — Caledonia Springs — in which are hatched out and distributed 

 annually 4,000.000 to 5,000,000 of impregnated eggs and young. * 



Count M. de Causans, on the 10th of December, 1858, t the lake be- 



* One of the lierriug family, Alosa sapidissima (the shad), wliich in America is very 

 highly esteemed as an article of food, aud which, like the salmon, spawns in freshwater, 

 had been for some years almost iished out. Mr. Green has in the later years annually 

 hatched millions of young of this lish in open water — one year nearly 8,000,000 — so that 

 now the abundance in many places has become just as great as it was a hundred years 

 ago. The young have been carried from New York State to streams in California, 

 where they thrive well, although this fish did not before exist on the Pacific coast. A 

 couple of genera related to this fish are found sporadic on our coast. Would it not 

 be worth the trouble to attempt the introduction of the dainty shad to our coasts and 

 rivers ? 



t Bulletin de la Soci^t^ d'Acclimatation k Paris. 



